Cover film

ABSTRACT

A cover film having at least (A) a substrate layer, (B) an intermediate layer, (C) an adhesive layer, and (D) a heat seal layer having a heat sealable resin, a thermoplastic resin of the (D) heat sealing layer having a mixture of two types of (meth)acrylic acid ester copolymers having different glass transition temperatures and a hydrazide compound, wherein one of the (meth)acrylic acid ester copolymer in the (meth)acrylic acid ester copolymer mixture has a glass transition temperature of −20 to 10° C. and the other (meth)acrylic acid ester copolymer has a glass transition temperature of 40 to 80° C.

TECHNICAL FIELD

The present invention pertains to a cover film used in packages forelectronic components.

BACKGROUND ART

Alongside the miniaturization of electronic components, theminiaturization and performance of the electronic components used havealso continued to improve and components are automatically mounted onprinted circuit boards in assembly processes for electronic devices.Surface-mounted electronic components are stored in carrier tape inwhich pockets that are thermoformed in accordance with the shapes of theelectronic components so as to be able to store the same arecontinuously formed. After the electronic components are stored, a coverfilm is laid as a lid material on an upper surface of the carrier tapeand both edges of the cover film are continuously heat-sealed in thelongitudinal direction with a heated seal bar to form a package.Materials such as those in which a biaxially stretched polyester film islaminated onto a substrate and a thermoplastic resin heat seal layer islaminated thereon are used as cover film materials. Materials made fromthermoplastic resins such as polystyrene or polycarbonates are mainlyused as the carrier tape.

In recent years, various electronic components such as capacitors,resistors, ICs, LEDs, connectors, and switching elements have becomeremarkably small, lightweight, and thin and the required performancewhen peeling a cover film in order to extract a stored electroniccomponent from a package has become stricter than was conventional.

Electronic components transported, etc. by means of the carrier tapepackage have attained higher performance and have miniaturized alongsidewide-ranging improvements in surface-mounting techniques in recentyears. Static electricity is generated by such electronic componentsrubbing against the inner surfaces of an embossed carrier tape or innersurfaces of the cover film due to vibration during transport of carriertape packages and the electronic components may be damaged thereby.Further, there are cases of similar situations occurring due to staticelectricity generated when peeling a cover film from a carrier tape,etc. Accordingly, measures against static electricity for carrier tapesand cover tapes have been the most critical problems.

In a state in which electronic components are stored in a package, thepresence or absence of the components, the storage orientation of thecomponents, damage or bending of leads, etc. may be inspected. Alongsidethe miniaturization of electronic components in recent years, extremelyhigh transparency in cover films is necessary for the inspection ofcomponents stored in packages. Furthermore, friction generated betweenan electronic component and the heat seal layer of the cover filmimmediately following heat sealing or in a transportation environmentalso can inhibit inspection due to the heat seal surface whitening and,in addition to the abovementioned transparency, suppression of scrapingof the heat seal surface is also demanded.

As measures against scraping of heat seal surfaces, in addition tomethods for causing microparticles to protrude from the surface of aheat seal layer by adding 0.1 to 50% by mass of silica particles to anEVA-based heat seal layer so the thermoplastic resin and the componentdo not touch and adding electrically conductive microparticles such astin oxide or zinc oxide to a heat seal layer, there is also the exampleof setting the surface roughness Rz of a heat seal surface to at least1.0 μm (see Patent Documents 1 to 6). However, even if such methods cansuppress scraping of a heat seal surface of a cover film due to frictionwith electronic components, there are cases in which transparency fallsremarkably and the demanded performance cannot be satisfied and scrapingof a heat seal surface of a cover film due to friction with conventionalelectronic components was not considered as a problem.

CITATION LIST Patent Literature

-   Patent Document 1: JP H9-207988 A-   Patent Document 2: JP H9-201922 A-   Patent Document 3: JP H10-95448 A-   Patent Document 4: JP 2006-219137 A-   Patent Document 5: JP H8-258888 A-   Patent Document 6: JP 5983902 B

SUMMARY OF INVENTION Technical Problem

The present invention addresses the problem of providing a cover filmfor a polystyrene, polycarbonate, etc. carrier tape wherein the peelingstrength when peeling the cover film in order to extract an electroniccomponent is continuously within a predetermined range, increases inpeeling strength are small even during rapid peeling, trouble during themounting process such as minute electronic components protruding due tovibration when peeling or breakage of the cover film during rapidpeeling does not occur, the cover film is highly transparent, andwhitening due to friction with the electronic component does not occur.

Solution to Problem

As a result of diligent investigation of the abovementioned problem, theinventors, etc. discovered that a cover film that overcomes the problemof the present invention is obtained by providing a heat seal layercomprising a thermoplastic resin having a specific composition andarrived at the present invention.

That is, the present invention is a cover film comprising at least (A) asubstrate layer, (B) an intermediate layer, (C) an adhesive layer, and(D) a heat seal layer having a thermoplastic resin that is heat sealableto a carrier tape, the thermoplastic resin constituting the (D) heatseal layer comprising a mixture of two types of (meth)acrylic acid estercopolymers with different glass transition temperatures and a hydrazidecompound.The glass transition temperature of one of the (meth)acrylic acid estercopolymer in the (meth)acrylic acid ester copolymer mixture ispreferably from −20 to 10° C., more preferably from −20 to 0° C., andstill more preferably from −10 to 0° C. Further, the glass transitiontemperature of the other (meth)acrylic acid ester copolymer ispreferably from 40 to 80° C., more preferably from 40 to 70°, and stillmore preferably from 50 to 70°. Moreover, it is preferable that thereare 100 to 400 parts by mass of the (meth)acrylic acid ester copolymerwith the higher glass transition temperature with respect to 100 partsby mass of the (meth)acrylic acid ester copolymer with the lower glasstransition temperature and that there are 1 to 3 parts by mass of thehydrazide compound with respect to 100 parts by mass of the(meth)acrylic acid ester copolymer with the lower glass transitiontemperature.It is preferable that the carbon chain in the hydrazide compoundincluded in the (meth)acrylic acid ester copolymers that form the (D)heat seal layer has 1 to 4 carbon atoms.It is preferable that the (B) intermediate layer is formed from apolyolefin-based resin and the (C) adhesive layer is formed from: aresin composition containing a styrene-based resin having astyrene-diene block copolymer as a main component and anethylene-α-olefin random copolymer; a hydrogenate of an aromaticvinyl-conjugated diene copolymer comprising 15 to 35% by mass of amonomer unit derived from an aromatic vinyl compound; or anethylene-vinyl acetate copolymer comprising 75 to 91% by mass of amonomer unit derived from ethylene.It is preferable that the (D) heat seal layer contains an electricallyconductive material and further, that the shape of the electricallyconductive material comprises either needle-shaped or spheroidalmicroparticles or a combination thereof. Carbon nanomaterials arepreferable as other embodiments of the electrically conductive material.Meanwhile, the present invention encompasses an electronic componentpackage using the cover film as a lid material of a carrier tape thatcomprises a thermoplastic resin.

Advantageous Effects of Invention

In the present invention, a cover film for a polystyrene, polycarbonate,etc. carrier tape wherein the peeling strength when peeling the coverfilm in order to extract an electronic component is continuously withina predetermined range, trouble during the mounting process such asminute electronic components protruding due to vibration when peelingdoes not occur, the cover film is highly transparent, and whitening dueto friction with the electronic component does not occur is obtained.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 A cross-sectional view showing one example of the layerconfiguration of the cover film of the present invention.

FIG. 2 A structural formula showing one example of the dihydrazidecompound used in the present invention.

DESCRIPTION OF EMBODIMENTS

The cover film of the present invention comprises at least (A) asubstrate layer, (B) an intermediate layer, (C) an adhesive layer, and(D) a heat seal layer. The configuration of one example the cover filmof the present invention is shown in FIG. 1 . The (A) substrate layer isa layer comprising a biaxially stretched polyester or a biaxiallystretched nylon and biaxially stretched polyethylene terephthalate(PET), biaxially stretched ethylene naphthalate (PEN), and biaxiallystretched 6,6 nylon or 6-nylon can particularly suitably be used. Inaddition to materials normally used as biaxially stretched PET,biaxially stretched PEN, and biaxially stretched 6,6-nylon or 6-nylon,those to which an antistatic agent has been applied or into which anantistatic agent has been kneaded for an antistatic treatment or thoseto which a corona treatment, an adhesion-facilitating treatment, etc.has been performed can be used. If the substrate layer is too thin, thetensile strength of the cover film itself decreases and “film breakage”therefore readily occurs when peeling the cover film. Conversely, if thesubstrate layer is too thick, this not only invites decreases in heatsealing to the carrier tape, but rises in costs, so normally, asubstrate layer with a thickness of 12 to 25 μm can suitably be used.

In the present invention, the (B) intermediate layer can be provided bylaminating the same to one side of the (A) substrate layer via an anchorcoat layer. Linear low-density polyethylene (hereafter indicated asLLDPE), which has particular flexibility and appropriate stiffness andhas excellent tear strength at room temperature, can suitably be used asthe resin constituting the (B) intermediate layer and, by using a resinhaving a density in the range of 0.880 to 0.925 (×10³ kg/m³) inparticular, not only does staining of the iron when heat sealing notreadily occur due to protrusion of the intermediate resin layer from theend of the cover film not readily occurring due to heat or pressure whenheat sealing, but a stable peeling strength when peeling the cover filmis easily obtained because uneven contact with the heat seal iron ismitigated due to the intermediate layer softening when heat sealing thecover film.

In LLDPEs there are those polymerized by a Ziegler type catalyst andthose catalyzed by metallocene-based catalysts (hereafter indicated asm-LLDPE). The molecular weight distribution of m-LLDPEs is narrowlycontrolled and they therefore have a particularly high tear strength andan m-LLDPE, in particular, is preferably used as the (B) intermediatelayer of the present invention.

The m-LLDPE is a copolymer of ethylene and an olefin having a carbonnumber of at least 3 as a comonomer, preferably a linear or branchedaromatic core-substituted α-olefin with a carbon number of 3 to 18. Forexample, propylene, 1-butene, 1-pentene, 1-hexene, 1-octene, 1-nonene,1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, etc.are raised as linear monoolefins. Further, for example,3-methyl-1-butene, 3-methyl-1-pentene, 4-methyl-1-pentene,2-ethyl-1-hexene, etc. can be raised as branched monoolefins. Moreover,styrene, etc. are raised as examples of aromatic core-substitutedmonoolefins. These comonomers can be copolymerized with ethylene aloneor in a combination of two or more. In this copolymerization,copolymerization with a polyene such as butadiene, isoprene,1,3-hexadiene, dicyclopentadiene, or 5-ethylidine-2-norbornene may beperformed.

The thickness of the (B) intermediate layer is generally 5 to 50 μm andis preferably 10 to 40 μm. With a thickness of the (B) intermediatelayer of less than 5 μm, the effect of easing uneven contact of the heatseal iron when heat sealing the cover film to the carrier tape is notreadily obtained. Meanwhile, if a thickness of 50 μm is exceeded,sufficient peeling strength becoming difficult to obtain may occur whenheat sealing the cover film to the carrier tape due to the totalthickness of the cover film.

In the cover film of the present application, the (C) adhesive layer isprovided between the (B) intermediate layer and the (D) heat seal layer.The thermoplastic resin used in the (C) adhesive layer comprises any of:a resin composition containing a styrene-based resin having astyrene-diene block copolymer as a main component and anethylene-α-olefin random copolymer; a hydrogenate of an aromaticvinyl-conjugated diene copolymer in which the content of aromatic vinylgroups is 15 to 35% by mass; and an ethylene-vinyl acetate copolymercomprising 75 to 91% by mass of an olefin component, or a combinationthereof. Among these, a hydrogenate of a styrene-isoprene copolymer or ahydrogenate of a styrene-butadiene copolymer resin comprising a styreneratio of 15 to 35% by mass has little variation in peeling strength whenpeeling the cover film and can be suitably used.

The thickness of the (C) adhesive layer is normally in the range of 0.1to 15 μm and preferably in the range of 0.1 to 10 μm. When the thicknessof the (C) adhesive layer is less than 0.1 μm, sufficient peelingstrength may not be demonstrated when the cover film is heat sealed tothe carrier tape. Meanwhile, in cases in which the thickness of the (C)adhesive layer exceeds 15 μm, there is the risk of variance in peelingstrength when peeling the cover film arising. The (C) adhesive layer isnormally formed by extrusion film formation, but in cases in which thelayer has been formed by a coating method, the thickness stated here isthe post-drying thickness.

In order to prevent blocking when winding the cover film, spheroidal ormilled organic particles such as acrylic particles, styrene-basedparticles, or silicone-based particles or inorganic particles such astalc particles, silica particles, mica particles, calcium oxide, ormagnesium oxide can be added to the (C) adhesive layer. In particular,decreases in transparency are small when acrylic particles or silicaparticles are added and these can more suitably be used. The modediameter obtained from a mass distribution curve of the particles ispreferably 1 to 10 μm and still more preferably 2 to 7 μm. If the modediameter is less than 1 μm, the blocking prevention effect due to theparticle addition may not sufficiently manifest. Meanwhile, in cases inwhich the mode diameter exceeds 10 μm, the blocking prevention effectbecomes favorable, but the necessity of adding a large amount to preventblocking invites rises in costs and because visible irregularities ariseon the heat seal layer surface of the cover film, there is the risk ofthe external appearance of the cover film being impaired. The massfraction of the microparticles of the (C) adhesive layer is preferably 0to 15% by mass and still more preferably 5 to 10% by mass. In thisrange, the amount added is balanced between transparency, heat sealing,and blocking prevention effects.

In the cover film of the present application, the (D) heat seal layer isformed on a surface of the (C) adhesive layer. The thermoplastic resinof the (D) heat seal layer is (meth)acrylic acid ester copolymers. The(meth)acrylic acid ester copolymers are resins comprising one or more ofan acrylic acid ester such as methyl acrylate, ethyl acrylate, propylacrylate, or butyl acrylate, a methacrylic acid ester such as methylmethacrylate, ethyl methacrylate, propyl methacrylate, butylmethacrylate, cyclohexyl methacrylate, etc. and may be a resin in whichtwo or more of these have been copolymerized.

The (meth)acrylic acid ester copolymers constituting the (D) heat seallayer comprise two types of (meth)acrylic acid ester copolymers withdifferent glass transition temperatures. The glass transitiontemperature of one is preferably −20 to 10° C. and more preferably −10to 0° C. When the glass transition temperature is lower than −20° C.,there is the risk of variation in the peeling strength when peeling thecover film arising and furthermore, defects in which an electroniccomponent stored within a carrier tape adheres to the (D) heat seallayer of the cover tape or whitening occurring due to friction with theelectronic component may occur. Meanwhile, in cases in which the glasstransition temperature exceeds 10° C., elasticity of the (meth)acrylicacid ester copolymers that constitute the heat seal layer is notobtained and there is the possibility that whitening will occur due tofriction with the electronic component.

The glass transition temperature of the other (meth)acrylic acid estercopolymer is preferably 40 to 80° C. and more preferably 50 to 70° C. Atless than 40° C., the elasticity of the (D) heat seal layer decreasesand, as stated previously, whitening due to friction with an electroniccomponent may occur. Meanwhile, when the glass transition temperatureexceeds 80° C., film formation of the (D) heat seal layer is not stableand whitening due to friction with an electronic component may occur.

The glass transition temperatures are determined by differentialscanning calorimetry (DSC). An input compensation-type DSC8500manufactured by PerkinElmer Japan, Co., Ltd. was used as the device and,sealed with nitrogen gas, a sample amount of 5 mg of the (meth)acrylicacid ester copolymers was placed in an aluminum pan, rapidly cooled to−40° C., and data was obtained at a temperature elevation rate of 10degrees per minute and an interval of 0.01 seconds. The intersection ofa baseline and the tangent at the inflection point changing to theheat-absorption side as the temperature rises is read as and determinedto be the glass transition point.

The mixing ratio of the two types of (meth)acrylic acid ester copolymersis preferably 100 to 400 parts by mass of the (meth)acrylic acid estercopolymer with the higher glass transition temperature with respect to100 parts by mass of the (meth)acrylic acid ester copolymer with thelower glass transition temperature. If there are fewer than 100 parts bymass, elasticity of the heat seal layer decreases and, as statedpreviously, whitening due to friction with an electronic component mayoccur. Meanwhile, in cases in which there are greater than 400 parts bymass, film formation of the (D) heat seal layer is unstable andwhitening due to friction with an electronic component may occur.

A hydrazide compound is mixed with the (D) heat seal layer. Thehydrazide compound is generally a monohydrazide or a dihydrazidecompound, but from the objective of cross-linking the (meth)acrylic acidester copolymers to one another, the dihydrazide compound shown in FIG.2 is preferred. Among dihydrazide compounds, there are malonic aciddihydrazide in which the carbon chain is equivalent to C1 (the carbonchain shows 1), C2-equivalent succinic acid dihydrazide, C3-equivalentglutaric acid dihydrazide, C4-equivalent adipic acid dihydrazide, andC8-equivalent sebacic acid dihydrazide.

The carbon chain constituting the hydrazide compound is preferably a C1to 4 carbon chain. In cases in which C4 is exceeded, the compound ispoor in reactivity and there is the risk of sufficient elasticity of theheat seal layer not being obtained and whitening due to friction with anelectronic component may occur.

The mixing ratio of the hydrazide compound constituting the (D) heatseal layer is preferably 1 to 3 parts by mass with respect to 100 partsby mass of the (meth)acrylic acid ester copolymer with the lower glasstransition temperature. If there is less than 1 part by mass, reactionwith the (meth)acrylic acid ester copolymers does not sufficientlyprogress and there is the risk of whitening occurring due to frictionwith an electronic component. Meanwhile, if there are greater than 3parts by mass, the elasticity of the (D) heat seal layer becomes highand there is the possibility of variance in the peeling strength whenpeeling the cover film arising.

The (D) heat seal layer can contain at least one selected fromelectrically conductive tin oxide particles, electrically conductivezinc oxide particles, or electrically conductive titanium oxideparticles. Among these, electrical conductivity is increased by usingtin oxide doped with antimony, phosphorus, or gallium and there areminimal transparency decreases, so these can more suitably be used.Particles having a spheroidal or needle shape can be used as theelectrically conductive tin oxide particles, electrically conductivezinc oxide particles, or the electrically conductive titanium oxideparticles. In cases in which needle-shaped tin oxide particles dopedwith antimony are used, in particular, a cover film having especiallyfavorable antistatic performance is obtained. The amount added isnormally 100 to 1,000 parts by mass with respect to 100 parts by mass ofthe thermoplastic resin constituting the (D) heat seal layer and ispreferably 200 to 800 parts by mass. In cases in which the amount of theelectrically conductive particles added is less than 100 parts by mass,there is the risk of a cover film in which the surface resistivity valueof the (D) heat seal layer side is no greater than 10¹²Ω not beingobtained and if the amount exceeds 1,000 parts by mass, the relativeamount of the thermoplastic resin falls and therefore there is the riskthat sufficient peeling strength due to the heat seal will becomedifficult to obtain.

The (D) heat seal layer can contain at least one carbon nanomaterial ofcarbon nanotubes and carbon nanofibers. Among these, carbon nanotubeswith an aspect ratio of 10 to 10,000 are preferable. The amount added tothe (D) heat seal layer is 0.5 to 15 parts by mass with respect to 100parts by mass of the thermoplastic resin constituting the layer andpreferably 3 to 10 parts by mass. In cases in which the amount added isless than 0.5 parts by mass, the effect of imparting electricalconductivity by addition of the carbon nanomaterial is not sufficientlyobtained, whereas, if the amount exceeds 15 parts by mass, not only doesthis invite rises in costs, but also decreases in the transparency ofthe cover film, so inspection of a stored component through the coverfilm becomes difficult.

The thickness of the (D) heat seal layer is in the range of 0.1 to 5 μm,preferably 0.1 to 3 μm, and still more preferably 0.1 to 0.5 μm. Whenthe thickness of the heat seal layer is less than 0.1 μm, the (D) heatseal layer may not demonstrate sufficient peeling strength. Meanwhile,in cases in which the thickness of the heat seal layer exceeds 5 μm,this invites not only rises in costs, but variance in the peelingstrength when peeling the cover film also readily arises.

The method for fabricating the cover film is not particularly limitedand any general method can be used. For example, a two-layer filmcomprising (A) a substrate layer and (B) an intermediate layer isconfigured by applying an adhesive such as a polyurethane, polyester,polyolefin, or polyethyleneimine to a biaxially stretched polyester filmsurface of the (A) substrate layer, extruding a resin composition havingan m-LLDPE as a main component that serves as the (B) intermediate layerfrom a T-die, and coating a surface to which an anchor coating agent hasbeen applied with the same. Furthermore, the surface of the (B)intermediate layer can be coated with the (C) adhesive layer of thepresent invention by, for example, a gravure coater, a reverse coater, akiss coater, an air knife coater, a Mayer bar coater, a dip coater, etc.In this case, it is preferable that a corona treatment or ozonetreatment is performed on the (B) intermediate layer surface beforeapplying and performing a corona treatment is particularly preferable.Furthermore, the objective cover film can be obtained by coating the (C)adhesive layer applied to the (B) intermediate layer with a resincomposition constituting the (D) heat seal layer with a gravure coater,a reverse coater, a kiss coater, an air knife coater, a Mayer barcoater, a dip coater, etc.

As another method, a film comprising the (A) substrate layer biaxiallystretched polyester film, the (B) intermediate layer, and the (C)adhesive layer can be obtained by film-forming the (B) intermediatelayer and (C) the adhesive layer ahead of time with a T-die castingmethod, an inflation method, etc. and a dry lamination method thatadheres each film to the biaxially stretched polyester film of the (A)substrate layer via an adhesive such as a polyurethane, polyester, orpolyolefin and the objective cover film can also be obtained by applyingthe (D) heat seal layer to the surface of the (C) adhesive layer.

As yet another method, the objective cover film can also be obtained bya sandwich lamination method. That is, the film constituting the (C)adhesive layer is film-formed with a T-die casting method, an inflationmethod, etc. Then, the objective film can be obtained by supplying aresin composition having a molten m-LLDPE as a main component betweenthe (C) adhesive layer film and the (A) substrate layer film to form the(B) intermediate layer and laminating, obtaining a film comprising the(A) substrate layer, (B) intermediate layer, and (C) adhesive layer ofthe objective cover film, and further applying the (D) heat seal layerto the adhesive layer-side surface thereof. In the case of this method,similar to the abovementioned methods, using a film in which the surfaceof the side of the (A) substrate layer to be laminated is coated with anadhesive is common.

In addition to the abovementioned steps, an antistatic treatment can beperformed on the (A) substrate layer of the cover film, as necessary.For example, an anionic, cationic, non-ionic, betaine-based, etc.surfactant-type antistatic agent, an electrically conductive material inwhich a polymer-type antistatic agent and a binder have been dispersed,etc. can be applied as the antistatic agent with a roll coater using agravure roll, a lip coater, spraying, etc. Further, in order touniformly apply these antistatic agents, a corona discharge treatment oran ozone treatment is preferably performed on the film surface beforethe antistatic treatment and a corona discharge treatment isparticularly preferred.

The cover film is used as a lid material of a carrier tape, which is astorage container for electronic components. A carrier tape is abelt-like article with a width from about 8 mm to 100 mm having pocketsfor storing electronic components. In cases in which the cover film isheat sealed as a lid material, the material constituting the carriertape is not particularly limited and commercially available materialscan be used, for example, polystyrene, polyesters, polycarbonates,polyvinyl chlorides, etc. can be used. In cases in which an acrylicresin is used as the heat seal layer, the cover film is suitably used incombination with a polystyrene and/or polycarbonate carrier tape.Materials to which electrical conductivity has been imparted by kneadingcarbon black or carbon nanotubes in a resin, materials in which anantistatic agent or electrically conductive filler has been kneaded, ormaterials of which the surface has been coated with a surfactant-typeantistatic agent or a coating liquid in which an electrically conductivesubstance such as polypyrrole or polythiophene is dispersed in anorganic binder such as acryl and antistatic properties imparted can beused as the carrier tape.

Packages in which electronic components have been stored are obtainedby, for example, making a cover film into a lid material after storingan electronic component, etc. in an electronic component storage part ofa carrier tape, packaging by continuously heat sealing both edges of thecover film in the longitudinal direction thereof, and winding on a reel.Electronic components, etc. can be stored and transported by packagingin this form. While transporting a package in which electroniccomponents, etc. have been stored using holes, called sprocket holes,for carrier tape transport that are provided on the edges of the carriertape in the longitudinal direction thereof, the cover film isintermittently peeled and the presence, orientation, and position of theelectronic components, etc. are confirmed while these are extracted by acomponent mounting device and mounted on substrates.

Furthermore, when the cover film is peeled, if the peeling strength istoo little, there is the risk of peeling completely from the carriertape and the stored components falling out and if the peeling strengthis too great, there is the risk of peeling from the carrier tapebecoming difficult and also that breakage will occur when peeling thecover film, so when heat sealed at 120 to 220° C., a cover film having apeeling strength of 0.05 to 1.0 N is good and it is preferable thatvariation in the peeling strength is below 0.4 N.

EXAMPLES

The present invention shall be explained in detail below using examples,but the present invention is not limited thereby. In the examples andcomparative examples, the following resin raw materials are used in the(A) substrate layer, (B) intermediate layer, (C) adhesive layer, and (D)heat seal layer.

((A) Substrate Layer Resin)

(a-1) Substrate: E-5100 (manufactured by TOYOBO CO., LTD.), biaxiallystretched polyethylene terephthalate film, thickness: 16 μm

((B) Intermediate Layer Resin)

(b-1) m-LLDPE: Umerit 2040F (manufactured by UBE-MARUZEN POLYETHYLENE),MFR: 4.0 g/10 min (measurement temperature: 190° C., load: 2.16 kgf),density: 0.904×10³ kg/m³

((C) Adhesive Layer Resin)

(c-1-1) Resin: Tuftec H1041 (manufactured by Asahi Kasei ChemicalsCorporation), hydrogenated resin of a styrene-butadiene-styrene triblockcopolymer (SEBS), content of monomer units derived from styrene(hereafter referred to as styrene component content): 30% by mass(c-1-2) Resin: Denka Clearen (manufactured by Denka Company Limited),block copolymer comprising a styrene block-tapered block of styrene andbutadiene-styrene block, styrene component content: 84% by mass(c-1-3) Resin: TR Resin (manufactured by JSR Corporation),styrene-butadiene block copolymer, styrene component content: 43% bymass(c-1-4) Resin: Tafmer-A (manufactured by Mitsui Chemicals, Inc.),ethylene-1-butene random copolymer(c-1-5) Resin: Toyo Styrol E640N (manufactured by TOYO-STYRENE CO.,LTD.), high-impact polystyrene(c-1-6) Resin: Everflex V5711 (manufactured by DuPont-MitsuiPolychemicals Co. Ltd.), ethylene-vinyl acetate copolymer resin (EVA),content of monomer units derived from ethylene: 90% by mass((C) Microparticles in the Adhesive Layer)(c-2) Microparticles: PEX-ABT-16 (manufactured by TOKYO PRINTING INKMFG. CO., LTD.), talc and silica masterbatch (talc: 5% by mass, silica:45% by mass, low-density polyethylene: 50% by mass)((D) Heat Seal Layer Resin)(d-1-1) Resin: NK Polymer EC-242 (manufactured by Shin-Nakamura ChemicalCo., Ltd.), methyl methacrylate-butyl methacrylate-cyclohexylmethacrylate random copolymer emulsion, solid content concentration: 36%by mass, glass transition temperature: 60° C., does not contain ahydrazide compound(d-1-2) Resin: NK Polymer EC-300 (manufactured by Shin-Nakamura ChemicalCo., Ltd.), methyl methacrylate-butyl methacrylate-cyclohexylmethacrylate random copolymer emulsion, solid content concentration: 36%by mass, glass transition temperature: 0° C., 3 parts by mass of 4carbon chain hydrazine compound content with respect to 100 parts bymass of acrylic resin(d-1-3) Resin: NK Polymer EC-301 (manufactured by Shin-Nakamura ChemicalCo., Ltd.), methyl methacrylate-butyl acrylate-cyclohexyl methacrylaterandom copolymer emulsion, solid content concentration: 36% by mass,glass transition temperature: −10° C., 1 part by mass of 4 carbon chainhydrazine compound content with respect to 100 parts by mass of acrylicresin(d-1-4) Resin: NK Polymer EC-302 (manufactured by Shin-Nakamura ChemicalCo., Ltd.), methyl methacrylate-butyl acrylate-cyclohexyl methacrylaterandom copolymer emulsion, solid content concentration: 36% by mass,glass transition temperature: −10° C., 3 parts by mass of 4 carbon chainhydrazine compound content with respect to 100 parts by mass of acrylicresin(d-1-5) Resin: NK Polymer EC-303 (manufactured by Shin-Nakamura ChemicalCo., Ltd.), methyl methacrylate-butyl acrylate-cyclohexyl methacrylaterandom copolymer emulsion, solid content concentration: 36% by mass,glass transition temperature: −10° C., 5 parts by mass of 4 carbon chainhydrazine compound content with respect to 100 parts by mass of acrylicresin(d-1-6) Resin: NK Polymer EC-306 (manufactured by Shin-Nakamura ChemicalCo., Ltd.), methyl methacrylate-butyl acrylate-cyclohexyl methacrylaterandom copolymer emulsion, solid content concentration: 36% by mass,glass transition temperature: −10° C., 3 parts by mass of 8 carbon chainhydrazine compound content with respect to 100 parts by mass of acrylicresin(d-1-7) Resin: NK Polymer EC-307 (manufactured by Shin-Nakamura ChemicalCo., Ltd.), methyl methacrylate-butyl acrylate-cyclohexyl methacrylaterandom copolymer emulsion, solid content concentration: 36% by mass,glass transition temperature: −10° C., 3 parts by mass of 1 carbon chainhydrazine compound content with respect to 100 parts by mass of acrylicresin(d-1-8) Resin: NK Polymer EC-302NC (manufactured by Shin-NakamuraChemical Co., Ltd.), methyl methacrylate-butyl acrylate-cyclohexylmethacrylate random copolymer emulsion, solid content concentration: 36%by mass, glass transition temperature: −10° C., no hydrazine compoundcontent(d-1-9) Resin: NK Polymer EC-310 (manufactured by Shin-Nakamura ChemicalCo., Ltd.), methyl methacrylate-butyl acrylate-cyclohexyl methacrylaterandom copolymer emulsion, solid content concentration: 36% by mass,glass transition temperature: 10° C., 3 parts by mass of 4 carbon chainhydrazine compound content with respect to 100 parts by mass of acrylicresin(d-1-10) Resin: NK Polymer EC-311 (manufactured by Shin-NakamuraChemical Co., Ltd.), methyl methacrylate-butyl acrylate-cyclohexylmethacrylate random copolymer emulsion, solid content concentration: 36%by mass, glass transition temperature: −20° C., 3 parts by mass of 4carbon chain hydrazine compound content with respect to 100 parts bymass of acrylic resin(d-1-11) Resin: NK Polymer EC-312 (manufactured by Shin-NakamuraChemical Co., Ltd.), methyl methacrylate-butyl acrylate-cyclohexylmethacrylate random copolymer emulsion, solid content concentration: 36%by mass, glass transition temperature: 60° C., 3 parts by mass of 4carbon chain hydrazine compound content with respect to 100 parts bymass of acrylic resin(d-1-12) Resin: NK Polymer EC-24 (manufactured by Shin-Nakamura ChemicalCo., Ltd.), methyl methacrylate-butyl acrylate-cyclohexyl methacrylaterandom copolymer emulsion, solid content concentration: 36% by mass,glass transition temperature: 80° C., no hydrazine compound content(d-1-13) Resin: NK Polymer EC-2424 (manufactured by Shin-NakamuraChemical Co., Ltd.), methyl methacrylate-butyl acrylate-cyclohexylmethacrylate random copolymer emulsion, solid content concentration: 36%by mass, glass transition temperature: 40° C., no hydrazine compoundcontent((D) Electrically Conductive Agent Added to Heat Seal Layer)(d-2-1) Electrically Conductive Agent: SN-100D (manufactured by ISHIHARASANGYOU KAISHA, LTD.), spheroidal antimony-doped tin oxide, numberaverage long diameter: 0.1 μm, aqueous dispersion type, solid contentconcentration: 30% by mass(d-2-2) Electrically Conductive Agent: FS-10D (manufactured by ISHIHARASANGYOU KAISHA, LTD.), needle-shaped antimony-doped tin oxide, numberaverage length: 2 μm, aqueous dispersion type, solid contentconcentration: 20% by mass(d-2-3) Electrically Conductive Agent: DCNT240D-1 (manufactured by DAIDOCORPORATION), carbon nanotubes, solid content concentration: 1 wt. %((D) Inorganic Filler Added to Heat Seal Layer)(d-3-1) Inorganic Filler: W630 (manufactured by Evonik Japan Co., Ltd.)spheroidal alumina, number average long diameter: 0.1 μm, aqueousdispersion type, solid content concentration: 30% by mass

Example 1

As a resin constituting the (C) adhesive layer, a resin compositionconstituting an adhesive layer was obtained by pre-blending 80% by massof a hydrogenated resin of a styrene-butadiene-styrene triblockcopolymer (“Tuftec H1041” manufactured by Asahi Kasei ChemicalsCorporation, styrene component content: 30% by mass) and 20% by mass ofa talc and silica masterbatch (“PEX-ABT-16” manufactured by TOKYOPRINTING INK MFG. CO., LTD.) in a tumbler and kneading at 200° C. usinga 40 mm diameter single-screw extruder and extruding at a line rate of20 m per minute. This resin composition and, as an olefin-based resinconstituting the (B) intermediate layer, a metallocene linearlow-density polyethylene (“Umerit 2040F” manufactured by UBE-MARUZENPOLYETHYLENE) were extruded from separate single-screw extruders and, bylaminate-extruding with a multi-manifold T-die, a two-layer film inwhich the thickness of the (C) adhesive layer is 10 μm and the thicknessof the (B) intermediate layer is 20 μm was obtained. Next, an anchorcoat layer was formed on one surface of a biaxially stretchedpolyethylene terephthalate film that is the (A) substrate layer(thickness: 16 μm, “E-5100” manufactured by TOYOBO CO., LTD.) with agravure method such that the post-drying thickness becomes 3 μm using atwo liquid curing-type adhesive comprising a polyester-based resin(“LIOSTAR 1000” manufactured by Toyo-Morton, Ltd.) as a main agent and ahexamethylene diisocyanate/isophorone diisocyanate (“LIOSTAR 500H”manufactured by Toyo-Morton, Ltd.) as a curing agent and this was pastedto the (B) intermediate layer surface of the two-layer film with a drylamination method. A cover film for an electronic component carrier tapewith the configuration shown in FIG. 1 was obtained by, after a coronatreatment was performed on the (C) adhesive layer, applying a solutioncomprising 5% by mass of a methyl methacrylate-butyl acrylate-cyclohexylmethacrylate random copolymer in which a hydrazide compound is mixed[(d-1-2) resin emulsion], 15% by mass of a methyl methacrylate-butylacrylate-cyclohexyl methacrylate random copolymer [(d-1-1) resinemulsion], and 80% by mass of an electrically conductive agent [(d-2-1)electrically conductive filler dispersion] so as to have a post-dryingthickness of 0.3 μm to form the (D) heat seal layer (the anchor coatlayer is not illustrated).

Examples 2 to 19 and Comparative Examples 1 to 4

Cover films were created in the same manner as Example 1 other than the(C) adhesive layer and the (D) heat seal layer being formed using theraw materials such as resins described in Tables 1 to 3.

Comparative Example 5

A cover film was created in the same manner as Example 1 other than the(D) heat seal layer being formed without providing the (C) adhesivelayer and the thickness of the (B) intermediate layer being set to 30μm.

Comparative Example 6

A cover film was created in the same manner as Example 1 other than the(B) intermediate layer not being provided and the (C) adhesive layerbeing formed using the raw materials described in Table 2 and thethickness thereof being set to 30 μm.

Evaluation Method

The cover films for an electronic component carrier tape fabricated inthe examples and comparative examples were evaluated as shown below. Theresults thereof are collectively shown in Tables 1 to 3.

(1) Haze Value

The haze value was measured using an integrating sphere-type measurementdevice in accordance with Measurement Method A of JIS K 7105:1998. Theresults are shown in the haze value row in Tables 1 to 3.

(2) Sealing

Using a taping machine (ETM-480 manufactured by SHIBUYA CORPORATION), a5.5 mm width cover film was heat sealed to an 8 mm width polycarbonatecarrier tape (manufactured by Denka Company Limited) and a polystyrenecarrier tape (manufactured by Denka Company Limited) with a seal headwidth of 0.5 mm×2, a seal head length of 32 mm, a seal pressure of 0.1MPa, a feed length of 4 mm, a seal period of 0.1 seconds×8 times at aseal iron temperature of 10° C. intervals from 140 to 190° C. Afterbeing left for 24 hours in an atmosphere with a temperature of 23° C.and a relative humidity of 50%, the cover films were peeled at a rate of300 mm per minute and a peeling angle of 170 to 180° in the sameatmosphere with a temperature of 23° C. and a relative humidity of 50%and those having an average peeling strength in the range of 0.3 to 0.9N when heat sealed with a seal iron temperature at 10° C. intervals from140 to 190° C. are marked as “excellent”, those having an averagepeeling strength that falls outside the range of 0.3 to 0.9 N when heatsealed with a seal iron temperature at 10° C. intervals from 140 to 190°C. although the seal iron temperature range is that in which the averagepeeling strength becomes 0.3 to 0.9 N are marked as “good”, and those inwhich the average peeling strength is not in the region of 0.3 to 0.9 Nat any seal iron temperature are marked as “poor”. The results are shownin the sealing row in Tables 1 to 3.(3) Variation in Peeling StrengthHeat sealing was performed so that the peeling strength with respect tothe polystyrene carrier tape (manufactured by Denka Company Limited)becomes 0.4 N. The cover films were peeled under the same conditions asin (2) Sealing. The variance in peeling strength was derived from achart obtained when a 100 mm portion of a cover film was peeled in thepeeling direction. Those in which the variation of the peeling strengthwas no greater than 0.2 N were described as “excellent”, those in whichthe variation was from 0.2 to 0.4 N were described as “good”, and thosein which the variation was greater than 0.4 N were described as “poor”.The results are shown in the Variation in Peeling Strength row in Tables1 to 3.(4) Friction with Electronic Component TestingAfter an electronic component (SOT-223-6 manufactured by TexasInstruments Inc., 6.45 mm×3.45 mm×1.80 mm) was loaded in a polycarbonatecarrier tape (manufactured by Denka Company Limited) in an atmospherewith a temperature of 23° C. and a relative humidity of 50%, a covertape was heat sealed at 190° C. and a 20 cm tape cut sample wasproduced. A vibration tester (environmental vibration tester CV-101) wasfixed to one side of the tape cut sample and friction vibration testingwith the electronic component performed with a frequency of 20 Hz, anacceleration of 1.5 G, an amplitude of 2 mm, and a time period of 1minute. Those in which there was no damage to the heat seal surface ofthe cover tape were marked as “excellent”, those in which there wasdamage to one location within the four corners of the electroniccomponent were marked as “good”, and those with damage at two or morelocations were marked as “poor”. The results are shown in the frictiontest row in Tables 1 to 3.(5) Temporal Stability of Peeling StrengthHeat sealing was performed under the same conditions as in (2) Sealingsuch that the peeling strength becomes 0.4 N. Measurement of the peelingstrength was performed after placing the cover tapes in an environmentwith a temperature of 60° C. and a relative humidity of 10% and anenvironment with a temperature of 60° C. and a relative humidity of 90%for seven days and then, after removing the cover tapes, leaving themfor 24 hours in an atmosphere with a temperature of 23° C. and arelative humidity of 50% in the same atmosphere with a temperature of23° C. and a relative humidity of 50%. The measurements of peelingstrength were performed under the same conditions as in (2) Sealing.Those in which the average peeling strength was in the range of 0.4±0.1N were marked as “excellent”, those in which the average peelingstrength was in the range of 0.4±0.2 N were marked as “good”, and thosewith an average peeling strength outside this range were marked as“poor”. The results are shown in the peeling strength row in Tables 1 to3.(6) Surface ResistivityThe surface resistivity of the heat seal layer surface was measured withthe method of JIS K 6911 using a Hiresta UP MCP-HT450 manufactured byMitsubishi Chemical Corporation at an atmospheric temperature of 23° C.,an atmospheric humidity of 50% RH, and with an applied voltage of 10 V.The results are shown in the surface resistivity row in Tables 1 to 3.

TABLE 1 Layer Configuration Example 1 Example 2 Example 3 Example 4Example 5 Substrate o-PET a-1 E-5100 100 100 100 100 100 LayerIntermediate m-LLDPE b-1 2040F 100 100 100 100 100 Layer Adhesive Resinc-1-1 Tuftec Styrene-butadiene-styrene 80 80 80 80 80 Layer Blend H1041triblock copolymer hydrogenated resin Resin c-1-2 DenkaStyrene-butadiene block Clearen copolymer Resin c-1-3 TR ResinStyrene-butadiene block copolymer Resin c-1-4 Tafmer A Ethylene-1-butenerandom copolymer Resin c-1-5 Toyc Styrol High-impact polystyrene E640NResin c-1-6 Everflex Ethylene-vinyl acetate V5711 copolymerMicroparticles c-2 PEX-ABT- Talc and silica masterbatch 20 20 20 20 2016 Heat Seal Resin d-1-1 NK Acrylic copolymer emulsion, 15 15 15 15 15Layer Polymer Tg 60° C., no hydrazide Blend EC-242 compound contentResin d-1-2 NK Acrylic copolymer emulsion, 5 Polymer Tg 0° C., 3 partsby weight EC-300 C4 hydrazide compound content Resin d-1-3 NK Acryliccopolymer emulsion, 5 Polymer Tg −10° C., 1 part by weight EC-301 C4hydrazide compound content Resin d-1-4 NK Acrylic copolymer emulsion, 5Polymer Tg −10° C., 3 parts by weight EC-302 C4 hydrazide compoundcontent Resin d-1-5 NK Acrylic copolymer emulsion, 5 Polymer Tg −10° C.,5 parts by weight EC-303 C4 hydrazide compound content Resin d-1-6 NKAcrylic copolymer emulsion, 5 Polymer Tg −10° C., 3 parts by weightEC-306 C8 hydrazide compound content Resin d-1-7 NK Acrylic copolymeremulsion, Polymer Tg −10° C., 3 parts by weight EC-307 C1 hydrazidecompound content Resin d-1-8 NK Acrylic copolymer emulsion, Polymer Tg−10° C., no hydrazide EC-302NC compound content Resin d-1-9 NK Acryliccopolymer emulsion, Polymer Tg 10° C., 3 parts by weight EC-310 C4hydrazide compound content Resin d-1-10 NK Acrylic copolymer emulsion,Polymer Tg −20° C., 3 parts by weight EC-311 C4 hydrazide compoundcontent Resin d-1-11 NK Acrylic copolymer emulsion, Polymer Tg 60° C., 3parts by weight EC-312 C4 hydrazide compound content Resin d-1-12 NKAcrylic copolymer emulsion, Polymer Tg 80° C., no hydrazide EC-24compound content Resin d-1-13 NK Acrylic copolymer emulsion, Polymer Tg40° C., no hydrazide EC-2424 compound content Resin Mixing Low Tgacrylic 100:309:3 100:303:1 100:309:3 100:315:5 100:309:3 Ratiocopolymer:high Tg acrylic copolymer:hydrazide compound Electricallyd-2-1 SN-100D Spheroidal antimony-doped 80 80 80 80 80 Conductive tinoxide dispersion Agent Electrically d-2-2 FS-10D Needle-shaped antimony-Conductive doped tin oxide dispersion Agent Electrically d-2-3 DCNT-Carbon nanotube dispersion Conductive 240D-1 Agent Inorganic d-3-1 W630Spheroidal alumina dispersion Filler Evaluated Substrate Layer Thickess,μm 16 16 16 16 16 Physical Anchor Coat Layer Thickness, μm 3 3 3 3 3Properties, Intermediate Layer Thickness, μm 20 20 20 20 20 etc.Adhesive Layer Thickness, μm 10 10 10 10 10 Heat Seal Layer Thickness,μm 0.3 0.3 0.3 0.3 0.3 Cover Film Thickness, μm 49.3 49.3 49.3 49.3 49.3(1) Haze Value, % 17 17 17 17 17 (2) Sealing 1 To polycarbonate carriertape Excellent Excellent Excellent Excellent Excellent 2 To polystyrenecarrier tape Excellent Excellent Excellent Excellent Excellent (3)Variation in Peeling Strength Excellent Excellent Excellent GoodExcellent (4) Friction with Electronic Component Testing ExcellentExcellent Excellent Excellent Good (5) Temporal Stability of PeelingStrength Excellent Excellent Excellent Excellent Excellent (6) SurfaceResistivity, Ω 5.2.E+08 4.9.E+08 6.0.E+08 4.5.E+08 3.8.E+08 LayerConfiguration Example 6 Example 7 Example 8 Example 9 Substrate o-PETa-1 E-5100 100 100 100 100 Layer Intermediate m-LLDPE b-1 2040F 100 100100 100 Layer Adhesive Resin c-1-1 Tuftec Styrene-butadiene-styrenetriblock copolymer 80 80 80 80 Layer Blend H1041 hydrogenated resinResin c-1-2 Denka Styrene-butadiene block copolymer Clearen Resin c-1-3TR Resin Styrene-butadiene block copolymer Resin c-1-4 Tafmer AEthylene-1-butene random copolymer Resin c-1-5 Toyc Styrol High-impactpolystyrene E640N Resin c-1-6 Everflex Ethylene-vinyl acetate copolymerV5711 Microparticles c-2 PEX-ABT- Talc and silica masterbatch 20 20 2020 16 Heat Seal Resin d-1-1 NK Acrylic copolymer emulsion, Tg 60° C., no15 Layer Polymer hydrazide compound content Blend EC-242 Resin d-1-2 NKAcrylic copolymer emulsion, Tg 0° C., Polymer 3 parts by weight C4hydrazide EC-300 compound content Resin d-1-3 NK Acrylic copolymeremulsion, Tg −10° C., Polymer 1 part by weight C4 hydrazide EC-301compound content Resin d-1-4 NK Acrylic copolymer emulsion, Tg −10° C.,Polymer 3 parts by weight C4 hydrazide EC-302 compound content Resind-1-5 NK Acrylic copolymer emulsion, Tg −10° C., Polymer 5 parts byweight C4 hydrazide EC-303 compound content Resin d-1-6 NK Acryliccopolymer emulsion, Tg −10° C., Polymer 3 parts by weight C8 hydrazideEC-306 compound content Resin d-1-7 NK Acrylic copolymer emulsion, Tg−10° C., 5 5 5 Polymer 3 parts by weight C1 hydrazide EC-307 compoundcontent Resin d-1-8 NK Acrylic copolymer emulsion, Tg −10° C., Polymerno hydrazide compound content EC-302NC Resin d-1-9 NK Acrylic copolymeremulsion, Tg 10° C., 5 Polymer 3 parts by weight C4 hydrazide EC-310compound content Resin d-1-10 NK Acrylic copolymer emulsion, Tg −20° C.,Polymer 3 parts by weight C4 hydrazide EC-311 compound content Resind-1-11 NK Acrylic copolymer emulsion, Tg 60° C., Polymer 3 parts byweight C4 hydrazide EC-312 compound content Resin d-1-12 NK Acryliccopolymer emulsion, Tg 80° C., 15 Polymer no hydrazide compound contentEC-24 Resin d-1-13 NK Acrylic copolymer emulsion, Tg 40° C., 15 15Polymer no hydrazide compound content EC-2424 Resin Mixing Low Tgacrylic copolymer:high Tg 100:309:3 100:309:3 100:309:3 100:309:3 Ratioacrylic copolymer:hydrazide compound Electrically d-2-1 SN-100DSpheroidal antimony-doped tin oxide 80 80 80 80 Conductive dispersionAgent Electrically d-2-2 FS-10D Needle-shaped antimony-doped tin oxideConductive dispersion Agent Electrically d-2-3 DCNT- Carbon nanotubedispersion Conductive 240D-1 Agent Inorganic d-3-1 W630 Spheroidalalumina dispersion Filler Evaluated Substrate Layer Thickess, μm 16 1616 16 Physical Anchor Coat Layer Thickness, μm 3 3 3 3 Properties,Intermediate Layer Thickness, μm 20 20 20 20 etc. Adhesive LayerThickness, μm 10 10 10 10 Heat Seal Layer Thickness, μm 0.3 0.3 0.3 0.3Cover Film Thickness, μm 49.3 49.3 49.3 49.3 (1) Haze Value, % 17 19 1616 (2) Sealing 1 To polycarbonate carrier tape Excellent Good ExcellentExcellent 2 To polystyrene carrier tape Excellent Good ExcellentExcellent (3) Variation in Peeling Strength Excellent ExcellentExcellent Excellent (4) Friction with Electronic Component TestingExcellent Good Good Good (5) Temporal Stability of Peeling StrengthExcellent Excellent Excellent Excellent (6) Surface Resistivity, Ω6.0.E+08 5.1.E+08 5.7.E+08 6.5.E+08

TABLE 2 Example Example Example Example Example Layer Configuration 1011 12 13 14 Substrate o-PET a-1 E-5100 100 100 100 100 100 LayerIntermediate m-LLDPE b-1 2040F 100 100 100 100 100 Layer Adhesive Resinc-1-1 Tuftec Styrene-butadiene-styrene 80 80 80 80 80 Layer Blend H1041triblock copolymer hydrogenated resin Resin c-1-2 DenkaStyrene-butadiene block Clearen copolymer Resin c-1-3 TR ResinStyrene-butadiene block copolymer Resin c-1-4 Tafmer A Ethylene-1-butenerandom copolymer Resin c-1-5 Toyc Styrol High-impact polystyrene E640NResin c-1-6 Everflex Ethylene-vinyl acetate V5711 copolymerMicroparticles c-2 PEX-ABT- Talc and silica masterbatch 20 20 20 20 2016 Heat Seal Resin d-1-1 NK Acrylic copolymer emulsion, 10 15.8 30 39Layer Polymer Tg 60° C., no hydrazide Blend EC-242 compound contentResin d-1-2 NK Acrylic copolymer emulsion, 10 4.2 Polymer Tg 0° C., 3parts by weight EC-300 C4 hydrazide compound content Resin d-1-3 NKAcrylic copolymer emulsion, Polymer Tg −10° C., 1 part by weight EC-301C4 hydrazide compound content Resin d-1-4 NK Acrylic copolymer emulsion,Polymer Tg −10° C., 3 parts by weight EC-302 C4 hydrazide compoundcontent Resin d-1-5 NK Acrylic copolymer emulsion, Polymer Tg −10° C., 5parts by weight EC-303 C4 hydrazide compound content Resin d-1-6 NKAcrylic copolymer emulsion, Polymer Tg −10° C., 3 parts by weight EC-306C8 hydrazide compound content Resin d-1-7 NK Acrylic copolymer emulsion,10 13 Polymer Tg −10° C., 3 parts by weight EC-307 C1 hydrazide compoundcontent Resin d-1-8 NK Acrylic copolymer emulsion, Polymer Tg −10° C.,no hydrazide EC-302NC compound content Resin d-1-9 NK Acrylic copolymeremulsion, Polymer Tg 10° C., 3 parts by weight EC-310 C4 hydrazidecompound content Resin d-1-10 NK Acrylic copolymer emulsion, 5 PolymerTg −20° C., 3 parts by weight EC-311 C4 hydrazide compound content Resind-1-11 NK Acrylic copolymer emulsion, Polymer Tg 60° C., 3 parts byweight EC-312 C4 hydrazide compound content Resin d-1-12 NK Acryliccopolymer emulsion, Polymer Tg 80° C., no hydrazide EC-24 compoundcontent Resin d-1-13 NK Acrylic copolymer emulsion, 15 Polymer Tg 40°C., no hydrazide EC-2424 compound content Resin Mixing Low Tg acrylic100:309:3 100:103:3 100:387:3 100:309:3 100:309:3 Ratio copolymer:highTg acrylic copolymer:hydrazide compound Electrically d-2-1 SN-100DSpheroidal antimony-doped 80 80 80 Conductive tin oxide dispersion AgentElectrically d-2-2 FS-10D Needle-shaped antimony- 60 Conductive dopedtin oxide dispersion Agent Electrically d-2-3 DCNT- Carbon nanotubedispersion 3 Conductive 240D-1 Agent Inorganic d-3-1 W630 Spheroidalalumina dispersion 45 Filler Evaluated Substrate Layer Thickess, μm 1616 16 16 16 Physical Anchor Coat Layer Thickness, μm 3 3 3 3 3Properties, Intermediate Layer Thickness, μm 20 20 20 20 20 etc.Adhesive Layer Thickness, μm 10 10 10 10 10 Heat Seal Layer Thickness,μm 0.3 0.3 0.3 0.3 0.3 Cover Film Thickness, μm 49.3 49.3 49.3 49.3 49.3(1) Haze Value, % 20 17 17 16 20 (2) Sealing 1 To polycarbonate carriertape Excellent Excellent Excellent Excellent Excellent 2 To polystyrenecarrier tape Excellent Excellent Excellent Excellent Excellent (3)Variation in Peeling Strength Good Excellent Excellent ExcellentExcellent (4) Friction with Electronic Component Testing Good Good GoodExcellent Excellent (5) Temporal Stability of Peeling Strength GoodExcellent Excellent Excellent Excellent (6) Surface Resistivity, Ω4.1.E+08 3.2.E+08 2.6.E+08 3.3.E+08 7.8.E+08 Example Example ExampleExample Example Layer Configuration 15 16 17 18 19 Substrate o-PET a-1E-5100 100 100 100 100 100 Layer Intermediate m-LLDPE b-1 2040F 100 100100 100 100 Layer Adhesive Resin c-1-1 Tuftec Styrene-butadiene-styrene80 80 80 Layer Blend H1041 triblock copolymer hydrogenated resin Resinc-1-2 Denka Styrene-butadiene block 42.5 Clearen copolymer Resin c-1-3TR Resin Styrene-butadiene block 12.5 copolymer Resin c-1-4 Tafmer AEthylene-1-butene random 35 copolymer Resin c-1-5 Toyc StyrolHigh-impact polystyrene 10 E640N Resin c-1-6 Everflex Ethylene-vinylacetate 80 V5711 copolymer Microparticles c-2 PEX-ABT- Talc and silicamasterbatch 20 20 20 20 16 Heat Seal Resin d-1-1 NK Acrylic copolymeremulsion, 15 15 5 Layer Polymer Tg 60° C., no hydrazide Blend EC-242compound content Resin d-1-2 NK Acrylic copolymer emulsion, Polymer Tg0° C., 3 parts by weight C4 EC-300 hydrazide compound content Resind-1-3 NK Acrylic copolymer emulsion, Polymer Tg −10° C., 1 part byweight EC-301 C4 hydrazide compound content Resin d-1-4 NK Acryliccopolymer emulsion, Polymer Tg −10° C., 3 parts by weight EC-302 C4hydrazide compound content Resin d-1-5 NK Acrylic copolymer emulsion,Polymer Tg −10° C., 5 parts by weight EC-303 C4 hydrazide compoundcontent Resin d-1-6 NK Acrylic copolymer emulsion, Polymer Tg −10° C., 3parts by weight EC-306 C8 hydrazide compound content Resin d-1-7 NKAcrylic copolymer emulsion, 25 5 5 Polymer Tg −10° C., 3 parts by weightEC-307 C1 hydrazide compound content Resin d-1-8 NK Acrylic copolymeremulsion, 5 Polymer Tg −10° C., no hydrazide EC-302NC compound contentResin d-1-9 NK Acrylic copolymer emulsion, Polymer Tg 10° C., 3 parts byweight EC-310 C4 hydrazide compound content Resin d-1-10 NK Acryliccopolymer emulsion, Polymer Tg −20° C., 3 parts by weight EC-311 C4hydrazide compound content Resin d-1-11 NK Acrylic copolymer emulsion,15 15 Polymer Tg 60° C., 3 parts by weight EC-312 C4 hydrazide compoundcontent Resin d-1-12 NK Acrylic copolymer emulsion, Polymer Tg 80° C.,no hydrazide EC-24 compound content Resin d-1-13 NK Acrylic copolymeremulsion, 75 Polymer Tg 40° C., no hydrazide EC-2424 compound contentResin Mixing Low Tg acrylic 100:309:3 100:309:3 100:309:3 100:291:3100:291:3 Ratio copolymer:high Tg acrylic copolymer:hydrazide compoundElectrically d-2-1 SN-100D Spheroidal antimony-doped tin 80 80 80 80Conductive oxide dispersion Agent Electrically d-2-2 FS-10DNeedle-shaped antimony- Conductive doped tin oxide dispersion AgentElectrically d-2-3 DCNT- Carbon nanotube dispersion Conductive 240D-1Agent Inorganic d-3-1 W630 Spheroidal alumina dispersion FillerEvaluated Substrate Layer Thickess, μm 16 16 16 16 16 Physical AnchorCoat Layer Thickness, μm 3 3 3 3 3 Properties, Intermediate LayerThickness, μm 20 20 20 20 20 etc. Adhesive Layer Thickness, μm 10 10 1010 10 Heat Seal Layer Thickness, μm 0.3 0.3 0.3 0.3 0.3 Cover FilmThickness, μm 49.3 49.3 49.3 49.3 49.3 (1) Haze Value, % 15 19 17 17 17(2) Sealing 1 To polycarbonate carrier tape Excellent ExcellentExcellent Excellent Excellent 2 To polystyrene carrier tape ExcellentExcellent Excellent Good Good (3) Variation in Peeling StrengthExcellent Excellent Excellent Good Good (4) Friction with ElectronicComponent Testing Good Excellent Excellent Excellent Excellent (5)Temporal Stability of Peeling Strength Excellent Excellent ExcellentGood Good (6) Surface Resistivity, Ω >1.0E+14 5.9.E+08 5.5.E+08 3.2.E+082.4.E+08

TABLE 3 Compar- Compar- Compar- Compar- Compar- Compar- ative ativeative ative ative ative Layer Configuration Example 1 Example 2 Example3 Example 4 Example 5 Example 6 Substrate o-PET a-1 E-5100 100 100 100100 100 100 Layer Intermediate m-LLDPE b-1 2040F 100 100 100 100 100Layer Adhesive Resin c-1-1 Tuftec Styrene-butadiene- 80 80 80 80 LayerBlend H1041 styrene triblock copolymer hydrogenated resin Resin c-1-2Denka Styrene-butadiene 42.5 Clearen block copolymer Resin c-1-3 TRStyrene-butadiene 12.5 Resin block copolymer Resin c-1-4 TafmerEthylene-1-butene 35 A random copolymer Resin c-1-5 Toyc High-impact 10Styrol polystyrene E640N Resin c-1-6 Everflex Ethylene-vinyl V5711acetate copolymer Micro- c-2 PEX- Talc and silica 20 20 20 20 particlesABT-16 masterbatch Heat Seal Resin d-1-1 NK Acrylic copolymer 20 15 1515 Layer Polymer emulsion, Tg 60° Blend EC-242 C., no hydrazide compoundcontent Resin d-1-2 NK Acrylic copolymer 20 5 5 Polymer emulsion, Tg 0°C., EC-300 3 parts by weight C4 hydrazide compound content Resin d-1-3NK Acrylic copolymer Polymer emulsion, Tg −10° EC-301 C., 1 part byweight C4 hydrazide compound content Resin d-1-4 NK Acrylic copolymerPolymer emulsion, Tg −10° EC-302 C., 3 parts by weight C4 hydrazidecompound content Resin d-1-5 NK Acrylic copolymer Polymer emulsion, Tg−10° EC-303 C., 5 parts by weight C4 hydrazide compound content Resind-1-6 NK Acrylic copolymer Polymer emulsion, Tg −10° EC-306 C., 3 partsby weight C8 hydrazide compound content Resin d-1-7 NK Acrylic copolymerPolymer emulsion, Tg −10° EC-307 C., 3 parts by weight C1 hydrazidecompound content Resin d-1-8 NK Acrylic copolymer 5 Polymer emulsion, Tg−10° EC- C., no hydrazide 302NC compound content Resin d-1-9 NK Acryliccopolymer Polymer emulsion, Tg 10° C., EC-310 3 parts by weight C4hydrazide compound content Resin d-1-10 NK Acrylic copolymer Polymeremulsion, Tg −20° EC-311 C., 3 parts by weight C4 hydrazide compoundcontent Resin d-1-11 NK Acrylic copolymer 20 Polymer emulsion, Tg 60°C., EC-312 3 parts by weight C4 hydrazide compound content Resin d-1-12NK Acrylic copolymer Polymer emulsion, Tg 80° C., EC-24 no hydrazidecompound content Resin d-1-13 NK Acrylic copolymer Polymer emulsion, Tg40° C., EC-2424 no hydrazide compound content Resin Low Tg acrylic300:100:0 100:309:3 100:309:3 Mixing copolymer:high Ratio Tg acryliccopolymer:hydrazide compound Electrically d-2-1 SN- Spheroidal 80 80 8080 80 80 Conductive 100D antimony-doped tin Agent oxide dispersionElectrically d-2-2 FS-10D Needle-shaped Conductive antimony-doped tinAgent oxide dispersion Electrically d-2-3 DCNT- Carbon nanotubeConductive 240D-1 dispersion Agent Inorganic d-3-1 W630 Spheroidalalumina Filler dispersion Evaluated Substrate Layer Thickess, μm 16 1616 16 16 16 Physical Anchor Coat Layer Thickness, μm 3 3 3 3 3 3Properties, Intermediate Layer Thickness, μm 20 20 20 20 30 0 etc.Adhesive Layer Thickness, μm 10 10 10 10 0 30 Heat Seal Layer Thickness,μm 0.3 0.3 0.3 0.3 0.3 0.3 Cover Film Thickness, μm 49.3 49.3 49.3 49.349.3 49.3 (1) Haze Value, % 17 16 17 17 17 17 (2) Sealing 1 Topolycarbonate carrier tape Excellent Excellent Excellent Excellent PoorPoor 2 To polystyrene carrier tape Excellent Excellent ExcellentExcellent Poor Poor (3) Variation in Peeling Strength ExcellentExcellent Excellent Excellent Poor Poor (4) Friction with ElectronicComponent Testing Poor Poor Poor Poor Excellent Excellent (5) TemporalStability of Peeling Strength Excellent Poor Excellent Excellent PoorPoor (6) Surface Resistivity, Ω 2.1.E+08 1.5.E+08 4.6.E+08 2.0.E+084.1.E+08 4.3.E+08

REFERENCE SIGNS LIST

-   1 Cover film-   2 Substrate layer-   3 Intermediate layer-   4 Adhesive layer-   5 Heat seal layer

The invention claimed is:
 1. A cover film comprising at least (A) a substrate layer, (B) an intermediate layer, (C) an adhesive layer, and (D) a heat seal layer having a heat sealable resin, a thermoplastic resin constituting the (D) heat seal layer comprising a mixture of two types of (meth)acrylic acid ester copolymers with different glass transition temperatures and a hydrazide compound, wherein one of the (meth)acrylic acid ester copolymers in the (meth)acrylic acid ester copolymer mixture has a glass transition temperature of −20 to 10° C. and the other (meth)acrylic acid ester copolymer has a glass transition temperature of 40 to 80° C. the (meth)acrylic acid ester copolymer with the higher glass transition temperature is 100 to 400 parts by mass with respect to 100 parts by mass of the (meth)acrylic acid ester copolymer with the lower glass transition temperature.
 2. The cover film according to claim 1, wherein one of the (meth)acrylic acid ester copolymer in the (meth)acrylic acid ester copolymer mixture has a glass transition temperature of −10 to 0° C. and the other (meth)acrylic acid ester copolymer has the glass transition temperature of 50 to 70° C.
 3. The cover film according to claim 1, wherein the hydrazide compound is 1 to 3 parts by mass with respect to 100 parts by mass of the (meth)acrylic acid ester copolymer with the lower glass transition temperature.
 4. The cover film according to claim 1, wherein the carbon chain in the hydrazide compound included in the (meth)acrylic acid ester copolymers that form the (D) heat seal layer is 1 to
 4. 5. The cover film according to claim 1, wherein the (B) intermediate layer is formed from a polyolefin-based resin and, the (C) adhesive layer is formed from: a resin composition containing a styrene-based resin having a styrene-diene block copolymer as a main component and an ethylene-α-olefin random copolymer; a hydrogenate of an aromatic vinyl-conjugated diene copolymer comprising 15 to 35% by mass of a monomer unit derived from an aromatic vinyl compound; or an ethylene-vinyl acetate copolymer comprising 75 to 91% by mass of a monomer unit derived from ethylene.
 6. The cover film according to claim 1, wherein the (D) heat seal layer contains an electrically conductive material and further, the shape of the electrically conductive material comprises either needle-shaped or spheroidal microparticles or a combination thereof.
 7. The cover film according to claim 1, wherein the (C) adhesive layer or the (D) heat seal layer contains an electrically conductive material and further, the electrically conductive material is a carbon nanomaterial.
 8. An electronic component package using the cover film according to claim 1 as a lid material of a carrier tape that comprises a thermoplastic resin. 